This invention relates to an induction system for an internal combustion engine and more particularly to an improved induction system that improves low speed running and efficiency.
It has been recently acknowledged that the idle in low speed performance of an internal combustion engine can be significantly improved by providing the intake charge to these chambers through a relatively small auxiliary induction passage. The use of such a small passage increases the velocity at which the charge enters the chamber and promotes turbulence in the chamber which may be maintained during the compression and ignition cycles. This increased turbulence improves flame propagation and significantly improves both fuel economy and the control of unwanted exhaust gas emissions at these low running conditions.
The aforenoted advantages may be gained and the construction of the engine simplified if the auxiliary induction system discharges into the main induction system close to its point of discharge into the chambers. Where, however, the combustion chamber is of the pent roof or bathtub type and is formed primarily in the cylinder head around the intake valves, certain disadvantages may result from such an arrangement. If a relatively small volume defining the combustion chamber surrounds the intake valve, the discharge from the auxiliary induction system may impinge upon the cylinder head walls which define the combustion chamber and the high velocity of the charge entering from the auxiliary intake passage will be dissipated. Furthermore, with such an arrangement it is difficult to control the actual flow in the chamber when the piston is commencing its compression stroke. That is, the wall of the cylinder head may deflect the flow of the charge from the auxiliary intake passage and prevent the desired flow pattern from being established in the cylinder during the compression and firing cycles.
It is, therefore, a principle object of this invention to provide an induction system for an internal combustion engine using an auxiliary intake system for supplying low speed charge requirements wherein the direction of flow from the auxiliary intake system may be accurately controlled.
It is another object of this invention to provide an auxiliary intake system for an internal combustion engine that discharges into the main intake system and which embodies an arrangement for controlling the direction of discharge from the auxiliary system into the chamber.
As has been noted, it is desirable to provide the discharge from the auxiliary intake system into the main intake system close to its point of discharge into the chamber. In connection with certain existing types of engines it may be difficult to achieve this without significantly modifying the cylinder head and its intake passages. That is, some existing type of engines do not readily lend themself to modification to incorporate an auxiliary induction system of the type previously described.
It is, therefore, a further object of this invention to provide a system whereby a conventional existing engine may be conveniently modified to incorporate an auxiliary induction system which will discharge into the main induction system of the engine.